[SR-13927] Unusual error with JSONDecoder

[swift-ci]

Previous ID	SR-13927
Radar	rdar://problem/71992646
Original Reporter	Hackice (JIRA User)
Type	Bug
Status	Reopened
Resolution

Attachment: Download

Environment

Xcode: Version 12.2 (12B45b)

macOS: 11.0.1 (20B29)

Mac: Mac mini (2018)

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug
Assignee	kylemacomber (JIRA)
Priority	Medium

md5: 8f09c902dd67e14883756601a56985b9

Issue Description:

When I used JSONDecoder to parse the Codable model, the compiler gave some meaningless error messages and no exception was thrown:

Sometimes the compiler will not display error in this case, but throws the exception "The given data did not contain a top-level value.", https://github.com/apple/swift/blob/main/stdlib/public/Darwin/Foundation/JSONEncoder.swift line: 1210, but obviously this is also meaningless, because my Model is just a very simple one-level struct.

Interestingly, the decode was successful after I commented out one of the attributes:

This is my json string:

{\"notification_id\":\"1107227364\",\"client_id\":\"14064\",\"user_id\":\"11857799\",\"create_user_id\":\"0\",\"refer_id\":\"0\",\"read_flag\":\"0\",\"pin_flag\":\"1\",\"enable_flag\":\"1\",\"module\":\"system\",\"title\":\"\"}

And Codable model:

struct Model: Codable {
    let notificationID, clientID, userID, createUserID: String?
    let referID, readFlag, pinFlag, enableFlag: String?
    let module: String?
    
    enum CodingKeys: String, CodingKey {
        case notificationID = "notification_id"
        case clientID = "client_id"
        case userID = "user_id"
        case createUserID = "create_user_id"
        case referID = "refer_id"
        case readFlag = "read_flag"
        case pinFlag = "pin_flag"
        case enableFlag = "enable_flag"
        case module
    }
}

[typesanitizer]

@swift-ci create

[swift-ci]

Comment by Kyle Macomber (JIRA)

I'm not able to reproduce this. Can you check if this still occurs on Xcode 12.3 (12C33)?

[swift-ci]

Comment by Wang Yanbing (JIRA)

Hi，kylemacomber (JIRA User)，

Xcode 12.3 (12C33) still occurs this problem. `error: Execution was interrupted, reason: EXC_BAD_ACCESS (code=EXC_I386_GPFLT).`

To reproduce, create a new Playground project and paste the following code into the default page:

let data = "{\"notification_id\":\"1107227364\",\"client_id\":\"14064\",\"user_id\":\"11857799\",\"create_user_id\":\"0\",\"refer_id\":\"0\",\"read_flag\":\"0\",\"pin_flag\":\"1\",\"enable_flag\":\"1\",\"module\":\"system\",\"title\":\"\"}".data(using: .utf8)!


import Foundation

struct Model: Codable {
    let notificationID, clientID, userID, createUserID: String?
    let referID, readFlag, pinFlag, enableFlag: String?
    let module: String?
    
    enum CodingKeys: String, CodingKey {
        case notificationID = "notification_id"
        case clientID = "client_id"
        case userID = "user_id"
        case createUserID = "create_user_id"
        case referID = "refer_id"
        case readFlag = "read_flag"
        case pinFlag = "pin_flag"
        case enableFlag = "enable_flag"
        case module
    }
}

do {
    let decode = try JSONDecoder().decode(Model.self, from: data)
    print(decode)
} catch {
    print(error)
}